The present invention generally relates to exposure data forming (i.e., organizing) methods, pattern forming methods, pattern exposure methods and pattern exposure apparatuses. More particularly, the present invention relates to an exposure data forming method for forming exposure data in which non-compressed and compressed exposure patterns coexist, a pattern forming method for forming a pattern using such an exposure data, and pattern exposure method and apparatus for exposing a pattern using such an exposure data.
Recently, there are demands to further improve the integration density and operation speed of large scale integrated circuit (LSI) devices. In order to meet such demands, a reticle or the like is used to form a pattern in a charged particle beam exposure apparatus. In the reticle, the original pattern or mask is enlarged with a predetermined magnification.
The original pattern of the semiconductor device is divided into basic unit patterns such as rectangular and trapezoidal patterns, and the exposure process is carried out using exposure data related to such basic unit patterns. For example, when producing a memory device having a memory capacity of several Mbits, a compressed exposure pattern having a hierarchical data structure is used for a memory cell because the memory cell is made up of a repetition of basic patterns. On the other hand, a peripheral circuit of the memory device is made up of non-repeating patterns, and non-compressed exposure patterns are used for the peripheral circuit. Accordingly, exposure data, of an extremely large quantity due to the large integration density, are effectively compressed and simplified.
However, when carrying out the exposure process on the exposure data in which the non-compressed and compressed exposure patterns coexist, a stage which carries an object which is to be subjected to the exposure must make unnecessary moves. As a result, there are problems in that it takes a long time to carry out the exposure process and the throughput of the exposure apparatus becomes poor.
Therefore, there are demands for an exposure data forming method which forms exposure data which enable efficient exposure, and to afford a pattern exposure method and a related apparatus which carry out such an efficient exposure. There are also demands to realize a pattern forming method which forms a pattern of a mask, reticle or a semiconductor device using such an efficient exposure.
FIG. 1A generally shows an example of a conventional electron beam exposure apparatus, and FIG. 1B shows a scanning locus of an electron beam. FIG. 2 generally shows an exposure process of the conventional electron beam exposure apparatus.
The electron beam exposure apparatus shown in FIG. 1A includes an electron gun 3 for emitting an electron beam 3a, an exposure data processor 2 for outputting deflection data D22 and moving (i.e., movement) data D12 in response to exposure data PD2, a deflector driver 4 for deflecting the electron beam 3a based on the deflection data D22, a stage driver 5 for moving a stage which carries an object 1 which is to be exposed based on the moving (i.e., movement) data D12, and a controller 6. The controller 6 controls input and output of the electron gun 3, the exposure data processor 2, the deflector driver 4 and the stage driver 5.
The electron beam 3a emitted from the electron gun 3 is deflected responsive to the deflection data D22 which is subjected to data processing based on the exposure data PD2. As a result, an LSI pattern, for example, is exposed on the object 1 which is moved by the stage based on the moving (i.e., movement) data D12.
When producing a memory device having a memory capacity on the order of several Mbits, for example, compressed exposure patterns are used for the memory cell which is made up of a repetition of basic patterns, while non-compressed exposure patterns are used for the peripheral circuit which is made up of non-repeating patterns. Hence, the exposure data PD2 is compressed and simplified.
However, because the non-compressed and compressed exposure patterns coexist, the stage and thus the object 1 must make unnecessary moves as will be described in conjunction with FIGS. 1B and 2.
FIG. 1B shows a scanning locus L of the electron beam 3a on the object 1 which carried on the stage. This scanning locus L is generated when each region of the object 1 to be exposed is moved, that is, when the stage which carries the object 1 moves. In FIG. 1B, regions a1 through a32 indicate regions in which the non-compressed exposure patterns are exposed, and regions b1 through b16 indicate regions in which the compressed exposure patterns are exposed. As shown, the scanning locus L of the electron beam 3a is complex.
The scanning locus L of the electron beam 3a becomes complex due to the exposure process shown in FIG. 2. For example, based on the exposure data PD2 in which the non-compressed and compressed exposure patterns coexist, a step P1 shown in FIG. 2 aligns the electron beam 3a relative to the region b1 in which the compressed exposure pattern is exposed. A step P2 carries out the exposure process for the regions b1 through b4. Next, a step P3 moves the electron beam 3a from the region b4 to the region b5. Thereafter, a step P4 carries out the exposure process for the regions b5 through b8.
Next, steps P5 through P8 are carried out. As a result, the region in which the compressed exposure pattern is exposed is successively changed from the region b8 and the exposure process is carried out for the regions b9 through b16. Then, a step P9 moves the electron beam 3a from the region b16 to the region a1 in which the non-compressed exposure pattern is exposed, and a step P10 carries out the exposure process for the regions a1 through a6. Steps P11 through P21 are carried out similarly, so that the region in which the non-compressed exposure pattern is exposed is successively changed from the region a6 and the exposure process is carried out for the regions a7 through a32.
The LSI pattern in which the non-compressed and compressed exposure patterns coexist is exposed through the above complex moves of the stages. For this reason, there is a problem in that the time it takes for the exposure process as a whole is considerably long due to the time required to move the stage so that the electron beam moves from one region to another adjacent region. Furthermore, there is a problem in that the throughput of the exposure apparatus becomes poor due to the long exposure time.